The present invention relates generally to an improved reciprocatory drive means and mounting therefor, and more particularly to a wobble shaft drive which is designed for use with heavy inertial loaded driven members, with the drive system providing positive drive motion to the driven member in a fashion which is substantially free of shock loading during change of direction, and thus functions substantially free of vibration.
The present invention is particularly adaptable for drive means wherein a relatively heavy elongated tool member is being driven along a reciprocatory path relative to a cutting bar member and wherein the drive means is mounted on the cutting bar member.
Typical of such applications is a sickle bar assembly wherein the cutter bar is driven along a reciprocatory cutting path relative to a cutting bar. In such an arrangement, therefore, the drive means of the present invention is coupled directly to the cutting bar, while reciprocatory motion is imparted to the cutter. The nature of the motion is essentially sine wave motion, and wherein closely aligned coupling between the drive means and the driven member provide for positive and substantially vibration-free operation.
The drive means of the present invention is ideally suited for use with a floating sickle bar system and for direct mounting on the cutting bar. Normally, a remote source of rotary motion is utilized to drive the mechanism, with a convenient drive pulley arrangement being capable of utilization.
Sickle bar arrangements are frequently used in the harvesting of cash or other crops, including such crops as soybeans, peas, milo or the like. Such devices are also widely used in weed cutting. In the past, it has been traditional to utilize a Pitman type drive wherein the sickle bar is braced by means of a brace-rod or stabilizer which is coupled between the frame of the harvesting machine and a point along the sickle bar frame. The coupling to the frame portion of the harvesting machine is generally disposed laterally outwardly and at an elevation above that at the point where energy or drive motion is being applied to the cutter bar. These arrangements have generally been unsatisfactory due to warping, flexing, or permanent deformation of the bracing rods, thus contributing to vibration, excessive wear, loss of timing, and ultimately to the creation of a substantial quantity of lost-motion in the drive arrangement and the presence of a substantial number of wearing components. The need for such brace-rods and stabilizers is eliminated since the drive is mounted directly to the cutting bar, and timing and alignment is preserved and constant.
In order to enhance the coupling arrangement between the wobble shaft and the driven member, a pair of ball and socket joints are provided which, when functioning together, deliver linear reciprocatory motion to the driven member, and with the motion being, as previously indicated, sine-wave motion free of abrupt changes of direction.